from machine import Pin
import utime
trigger = Pin(3, Pin.OUT)
echo = Pin(2, Pin.IN)
green = Pin(1, Pin.OUT)
red = Pin(5,Pin.OUT)
buzzeer = Pin(9,Pin.OUT)
Fuel_level=0
def ultra():
   trigger.low()
   utime.sleep_us(2)
   trigger.high()
   utime.sleep_us(5)
   trigger.low()
   while echo.value() == 0:
       signaloff = utime.ticks_us()
   while echo.value() == 1:
       signalon = utime.ticks_us()
   timepassed = signalon - signaloff
   Fuel_level = (timepassed * 0.0343) / 2
   return Fuel_level
   #print("The Fuel level in tank is ",Fuel_level,"cm")

previous_level=400

def detect_changes(previous_level, current_level):
    gradual_threshold = 5  
    sudden_threshold = 60  

    if abs(current_level - previous_level) > gradual_threshold:
        print("Gradual change detected!")
        green.on()
        red.off()
        buzzeer.off()

    if abs(current_level - previous_level) > sudden_threshold:
        print("Sudden change detected!")
        while(1):
            print("Theft Activity is happing .....")
            green.off()
            red.on()
            buzzeer.on()

while True:
        
   Fuel_level=ultra()
   print("The Fuel level in tank is ",Fuel_level,"cm")
   detect_changes(previous_level, Fuel_level)
   previous_level = Fuel_level

   utime.sleep(1)